OWASP Security Testing Checklist: Complete 2026 Guide

Last updated: June 29, 2026 · 9 min read

This OWASP security testing checklist gives you the complete framework for testing web applications and APIs in 2026 — covering the OWASP Top 10, the OWASP API Security Top 10, and hands-on test cases you can run today. For deeper tool walkthroughs, pair it with our Security Testing Tutorial and API Testing Tutorial.

• Average breach cost in 2026: $4.88 million (IBM)
• Regulatory pressure — GDPR, HIPAA, PCI-DSS, EU AI Act
• API is the new perimeter — 80%+ of attacks target APIs
• AI-generated code introduces new vulnerability classes — see our GitHub Copilot for QA guide.

A01 — Broken Access Control

TC — User cannot access other user's data
1. Log in as User A (id=123)
2. Try GET /users/124/profile
3. Expected: 403 Forbidden

TC — Admin endpoint protected
1. Log in as regular user
2. Try POST /admin/users
3. Expected: 403 Forbidden

A02 — Cryptographic Failures

TC — HTTPS enforced
1. Navigate to http://example.com
2. Expected: Redirect to https://example.com

TC — HSTS header present
1. Inspect response headers
2. Expected: Strict-Transport-Security present

TC — Cookies have HttpOnly and Secure
1. Log in
2. Inspect cookies in DevTools
3. Expected: HttpOnly and Secure flags set

A03 — Injection (SQL, NoSQL, LDAP, OS)

TC — SQL injection rejected
1. Enter ' OR '1'='1 as email
2. Expected: Validation error, no SQL executed

TC — XSS prevented
1. Enter <script>alert('xss')</script> as name
2. Expected: Script not rendered as code

TC — NoSQL injection rejected
1. Enter {"$gt": ""} as email
2. Expected: Validation error

A04 — Insecure Design

TC — Rate limiting on login
1. Submit wrong password 10 times
2. Expected: 429 Too Many Requests after threshold

TC — Critical ops require re-auth
1. Initiate password change
2. Expected: Re-authentication required

A05 — Security Misconfiguration

TC — Default credentials don't work
1. Try admin/admin, root/root
2. Expected: Authentication fails

TC — Security headers present
1. Inspect response headers
2. Expected: CSP, X-Frame-Options, X-Content-Type-Options

TC — Stack traces not exposed
1. Trigger an error in production
2. Expected: Generic error page, no stack trace

A06 — Vulnerable Components

TC — npm audit clean
1. Run npm audit
2. Expected: No high or critical vulnerabilities

TC — Dependencies within support window
1. List all dependencies
2. Expected: All within support window

A07 — Authentication Failures

TC — Password complexity enforced
1. Try password "123"
2. Expected: Rejected with complexity error

TC — Account lockout after failed attempts
1. Try wrong password 10 times
2. Expected: Account locked

TC — JWT validation
1. Modify JWT payload (don't change signature)
2. Expected: 401 Unauthorized

A08 — Data Integrity Failures

TC — Auto-update signatures verified
1. Trigger update
2. Expected: Signature verification passes

TC — Deserialization doesn't accept untrusted
1. Send malicious serialized data
2. Expected: Rejected

A09 — Logging Failures

TC — Failed login is logged
1. Submit wrong password
2. Check logs
3. Expected: Failed login event logged

TC — Privilege escalation is logged
1. Attempt to access admin endpoint as user
2. Check logs
3. Expected: Privilege escalation event logged

A10 — SSRF

TC — Server rejects internal URL fetch
1. POST /upload with URL http://localhost:8080/admin
2. Expected: Rejected

TC — AWS metadata blocked
1. POST /upload with URL http://169.254.169.254/
2. Expected: Rejected

Test every endpoint that takes an ID — pair this section with our API Testing Interview Questions and Postman API Testing Tutorial.

API1 — Broken Object Level Authorization (BOLA)

The #1 API vulnerability in 2026.

TC — User cannot access other user's object
1. Log in as User A (token_A, id=123)
2. GET /api/users/124 with token_A
3. Expected: 403 Forbidden

API2 — Broken Authentication

TC — Missing token rejected
1. GET /api/users without Authorization header
2. Expected: 401 Unauthorized

TC — Expired token rejected
1. Use expired JWT
2. Expected: 401 Unauthorized

API3 — Broken Object Property Level Authorization

TC — Cannot set admin role via API
1. PATCH /api/users/123 with {"role": "admin"}
2. Expected: 403 Forbidden or role ignored

API4 — Unrestricted Resource Consumption

TC — Rate limiting on API
1. Send 10,000 requests in 1 second
2. Expected: 429 Too Many Requests after threshold

TC — Large payload rejected
1. Send 100MB JSON payload
2. Expected: 413 Payload Too Large

API5 — Broken Function Level Authorization

TC — Regular user cannot access admin endpoint
1. Log in as regular user
2. POST /api/admin/users
3. Expected: 403 Forbidden

API6 — Unrestricted Sensitive Business Flows

TC — Coupon abuse prevented
1. Apply same coupon code 1,000 times
2. Expected: Rate limited or CAPTCHA after threshold

API7 — SSRF

TC — Internal URL fetch rejected
1. POST /api/upload with URL http://internal-service
2. Expected: Rejected

API8 — Security Misconfiguration

TC — CORS not too permissive
1. Request from external origin
2. Expected: CORS headers restrict origins

TC — Error messages don't leak details
1. Trigger error in production
2. Expected: Generic message, no stack trace

API9 — Improper Inventory Management

TC — Old API versions disabled
1. Try /api/v1/ (deprecated)
2. Expected: 404 Not Found

TC — Staging not exposed
1. Try /staging/, /dev/, /test/
2. Expected: Not accessible

API10 — Unsafe Consumption of APIs

TC — Third-party API responses validated
1. Mock third-party API with malformed response
2. Expected: App rejects or handles gracefully

SAST (Static Analysis)

SCA (Software Composition Analysis)

DAST (Dynamic Analysis)

Quick scan

docker run -v $(pwd):/zap/wrk:rw \
    owasp/zap2docker-stable zap-baseline.py \
    -t https://staging.example.com \
    -r zap-report.html

CI/CD integration

- name: OWASP ZAP Scan
  uses: zaproxy/action-baseline@v0.7.0
  with:
    target: 'https://staging.example.com'

Plug this into your existing pipeline patterns from our CI/CD Pipeline Testing Tutorial and GitHub Actions for Automation Testing guide.

For the full security bug report template, see our Security Testing Tutorial.

1 — Testing only with automated tools

Automated tools catch 30–50% of issues. Manual testing catches the rest.

2 — Not testing authentication thoroughly

Cover password complexity, account lockout, MFA bypass, JWT validation, and session timeout.

3 — Skipping authorization tests

For every endpoint, test anonymous access, wrong-role access, and right-role access.

4 — Not testing for BOLA

BOLA is the #1 API vulnerability. Walk IDs in URLs: /users/123 → /users/124.

5 — Trusting third-party APIs

Validate third-party API responses. Don't trust them blindly.

6 — Not testing error responses

500 errors shouldn't expose stack traces. 404s shouldn't reveal which resources exist.

7 — Not updating security tests

Threats evolve. Refresh your security test suite quarterly.

8 — Skipping rate limiting tests

Rate-limit logins, API calls, and resource creation to prevent abuse and DoS.

• Security Testing Tutorial
• Accessibility Testing WCAG Guide
• CI/CD Pipeline Testing Tutorial
• API Testing Tutorial

Official references: OWASP Top 10 · OWASP API Security Top 10 · OWASP ZAP.